Thursday, October 28, 2010

Tiny Flying Robots Modeled on Insects

Srinivasan and colleagues have developed helicopters that use image motion to hover over an arbitrary set of landmarks. The next step in mimicking an insect is the development of flapping-wing flight.

Enter aerospace engineer James De Laurier and his team of researchers at the Institute for Aerospace Studies at the University of Toronto in Canada. In collaboration with SRI International in Menlo Park, California, they are developing ornithoptersaircraft that get all of their thrust and most of their lift from flapping wings.

They are building a robotic ornithopter named Mentor, whose design was inspired by the study of small wasps in 1984 at Cambridge University in England, where scientists revealed that the flapping motion of insects produces extraordinary lift for such small wingspans.

The same flapping action is also found in hummingbirds and quail, said De Laurier. However, Mentor looks nothing like any flying creatures, having two sets of flapping and clapping wings to provide side-to-side stability.

"Mentor holds promise of not only achieving hover, but of also transitioning into efficient high-speed horizontal flight," said De Laurier. "Airplanes don't hover well, and helicopters are speed-limited."

When complete, De Laurier and his colleagues envision the aircraft being sent on missions that are considered too dangerous for humans, such as surveillance of a building damaged by an earthquake or reconnaissance of a terrorist situation.

Mars Exploration

Engineers at the Georgia Tech Research Institute (GTRI) at the Georgia Institute of Technology in Atlanta, in collaboration with the University of Missouri-Rolla, NASA's Glenn Research Center, and the Ohio Aerospace Institute in Cleveland, Ohio are building a fleet of robotic bugs that will scout the landscape of Mars.

The robots, called entomopters, were first developed by engineers at GTRI under a grant from the Defense Advanced Research Projects Agency to fly inside buildings and caves. On Mars, the robots can take advantage of the unique mechanics of insect flight to overcome many of the obstacles that the low density and gravity of the Martian atmosphere present to conventional aircraft.

"Insects work completely different from aircraft or birds by formation and shedding of vortices each time they flap their wings," said Anthony Colozza, an aerospace engineer with the Glenn Research Center, who coordinates entomopter work at the Ohio Aerospace Institute.

Airplanes require velocity to generate lift, and so in the low density of the Martian atmosphere they would either have to fly very fast or have wings with very large surface area.

Current technology limits the size of package that humans can send to Mars, so the best way to achieve flight with a conventional aircraft is with high velocity, which makes it difficult to land or turn around to take a second look at something of interest, said Colozza.

The entomopter, which uses a two-wing design and a chemical concoction for fuel, can land with precision, buzz off with ease, and engineers are working on its ability to hover. And because of the low density of the Martian atmosphere, scientists can build a robotic insect that is several feet long and still have the stability of an insect on Earth.

"Because the atmosphere is so thin, a larger entomopter should fly as adeptly on Mars as its tiny Earth-bound cousins do in our denser terrestrial air," said Robert Michelson, a research engineer at the Georgia Institute of Technology who leads the entomopter research.

If NASA continues to fund this research, once complete the scientists envision entomopters working alongside a lander or rover, which could serve as a launching pad and a refueling station. The entomopters could then fly around and make images of points of interest, perhaps even landing at some to collect samples.

Entomopters are also potentially quite useful on Earth, said Michelson, who originally designed the two-winged aircraft to perform indoor reconnaissance missions for the military. One such use, he said, would be to look for Al Queda operatives inside caves.

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